Apparatus for the continuous casting of metal slab



Aug. 21, 1951 ROSS] 2,564,723

APPARATUS FOR THE CONTINUOUS CASTING OF METAL SLABS Filed Nov. 6, 1947 ATTORNEY Patented Aug. 21, 1951 APPARATUS FOR THE CONTINUOUS CASTING OF METAL SLAB Irving Rossi, Morristown, N. J., assignor to Continuous Metalcast Corporation, Wilmington, Del., a corporation of Delaware Application November 6, 1947, Serial No. 784,467

3 Claims. (Cl. 22--57.2)

This invention relates to apparatus for the continuous casting of metal slab, it being understood that the term slab, as used herein, denotes a rectangular section having a width which greatly exceeds the thickness thereof. A typical slab for which the method is well adapted might have dimensions in the neighborhood of 18" x 54;", for example.

Inthe continuous casting of metal, and particularly in casting in accordance with the process described inJunghans Patents Nos. 2,135,183 and 2,135,184, molten metal is poured continuously into the upper end of a water cooled mold and solidified metal is withdrawn continuously from the other end, a pool of molten metal being maintained in the upper portion of the mold. In the casting of ingots and billets of round,

. square or even of rectangular shape in which the width does not exceed the thickness by more than four or five times, the inflowing molten metal spreads itself evenly across the mold, but when it is attempted to cast slab in this manner, it is found that the cooling eiiect of the closely spaced opposed mold walls is such that the spread of molten metal is so irregular and uneven that it has not been possible to cast slab satisfactorily in this manner.

It is an object of the present invention to overcome these clifiiculties.

Other objects and advantages of the invention will appear hereinafter. I

A preferred embodiment of the invention selected for purposes of illustration is shown in the accompanying drawings, in which,

Figure 1 is a top plan view of a mold liner.

Figure 2 is a section on the line 2-2 of Figure 1.

Referring to the drawings, the apparatus comprises a mold liner having opposed, spaced, parallel side walls I and 2, the upper portions of which are flared outwardly as shown at 3 and 4 to form an enlarged chamber 5 in which a pool of molten metal may be maintained. The end walls 6 and I of the liner are parallel from the top of the liner to the bottom. Furthermore, the end walls are preferably of uniform width from top to bottom and the flaring walls 3 and 4 coni verge at the ends of the mold so that the chamber 5, in the embodiment illustrated, is roughly diamond shaped.

Molten metal is flowed into the chamber 5 through a pipe or tube 8, the discharge end of which is submerged in the pool of molten metal.

The mold liner is made of any suitable material, but is preferably made of metal of relatively high heat conductivity such as copper and is relatively thin. The mold liner, as shown, is mounted on a suitable supporting plate or rim 9 and the exterior surfaces of the mold liner are surrounded and enclosed by a water jacket (not shown) through which cooling water may be circulated in contact with the exterior surfaces.

In the continuous casting of slab, using a mold liner as above described, it is necessary to maintain casting conditions such that the pool of molten metal (sometimes called the crater) extends well below the corners H) where the flaring portions of the liner merge with the parallel portions thereof. When such conditions are maintained, the shell of metal which solidifies slab is withdrawn from the bottom of the mold,

the hydrostatic pressure of the molten metal in the deep crater will cause the thin shell to bend as it passes the corners I0 to conform to the parallel mold surfaces where additional solidification takes place. Such conditions may be easily maintained, as well known in the art, merely by adjusting the rate of withdrawal and by correspondingly adjusting the rate of flow of molten metal supply. The faster the rate of withdrawal, of course, the deeper the crater, and the thinner the shell which will be formed by contact with the flaring portions of the liner.

It will be apparent that by flaring the upper portion of the mold liner, as above described, an increased surface area of molten metal is provided, together with an increased volume of molten metal in the pool, both of which contrib-v ute to rapid and even spreading of the molten metal from the point of discharge through the pipe 8 at the center of the mold to the ends of the mold. The angle of inclination of the flaring portions of the liner should, however, be kept as small as possible consistent with even spreading of the molten metal. This is important for two reasons. First, the smaller the angle, the less the solidified shell needs to be bent as it passes the corners l0. Second, the smaller the angle, the less the differential between the periphery of the interior of the flaring portion of the mold and the periphery of the interior of the straight portion of the mold. The importance of the latter may be explained by the fact that since the periphery of the interior of the flaring portion will always be greater than that of the straight portion, and since the periphery of the flaring portion decreases at successive levels approaching the corners ID, the shell of solidified metal formed by contact with the flaring portions must accommodate itself to this decrease, and it the angle of inclination is too great, wrinkles may be formed in the surface of the shell. It is to be noted, however, that shrinkage takes place as the shell solidifies, and so long as the angle is not too great this shrinkage will compensate adequately for the decreasing periphery. In general, it may be said that the flaring portions should'not be inclined at an angle of more than 20 to the vertical if wrinkles are to be avoided.

Furthermore. it is advisable to round the corners ll so that the shell will bend gradually as it moves past the corners.

It will be understood that the invention may be variously modified and embodied within the scope of the subjoined claims.

I claim as my invention:

1. A water cooled mold liner for the continuous casting of metal slab having a width which greatly exceeds the thickness thereof, comprising a lower portion having opposed, spaced, parallel side walls and opposed, spaced, parallel end walls, said side walls being of a width greatly exceeding the width of said end walls, and forming therewith an elongated, rectangular, vertically disposed mold.chamber, and an upper portion having opposed, spaced parallel end walls and opposed, spaced, outwardly diverging side walls forming an enlarged chamber in the upper portion of the mold in which a pool of molten metal may be maintained, said end walls being of uniform width throughout said upper and lower portions.

2. A water cooled mold liner for the continuous casting of metal slab having a width which greatly exceeds the thickness thereof, comprising a lower portion having opposed, spaced, parallel side walls and opposed, spaced, parallel end walls, said side walls being of a width greatly exceeding the width of said end walls, and forming therewith an elongated, rectangular, vertically disposed mold chamber, and an upp r P01- tion having opposed, spaced parallel end walls and opposed, spaced, outwardly diverging side walls, said end walls being of uniform width throughout said upper and lower portions said outwardly diverging side walls being inclined at an angle not greater than 20 to the vertical.

3. A water cooled mold liner for the continuous casting of metal slab having a width which greatly exceeds the thickness thereof, comprising a lower portion having opposed, spaced, parallel side walls and opposed, spaced, parallel end walls. said side walls being of a width greatly exceeding the width of said end walls, and form-' ing therewith an elongated, rectangular, vertically disposed mold chamber, an upper portion having opposed, spaced parallel end walls and opposed, spaced, outwardly diverging side walls forming, an enlarged chamber in the upper portion of the mold in which a pool of molten metal may be maintained, said end walls being of uniform width throughout said upper and lower portions,- and said upper portion being substantially diamond shapedin cross section.

'- IRVING R0881.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,344,577 Brasted June 22, 1020 1,567,363 Elrod et al. Dec. 29, 1925 1,567,431 Elrod Dec. 29, 1925 2,127,515 Hazelett Aug. 23, 1938 2,128,943 Hudson Sept. 6, 1938 2,225,415 Junghans Dec. 17, 1940 2,276,657 Junghans Mar. 17, 1942 FOREIGN PATENTS Number Country Date 439,494 France Apr. 11, 1012 

